Background:
The --bpf-lb-proto-diff option was introduced in v1.17 as part of #33434, and already defaults to true.

Proposal:
As lined out here, deprecate this option for v1.18 and then remove it in v1.19. Thus always create protocol-differentiated service entries in the controlplane, and support them in the datapath.

We keep the support for non-differentiated service entries, until we can be reasonably sure that all legacy entries have been migrated (maybe the LB controlplane already provides some auto-reconcile logic here?)